000
AXPZ20 KNHC 292206
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED JUL 29 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 86W/87W N OF 05N MOVING W 20 KT OVER THE 
PAST 24 HOURS. THE INTERACTION WITH AN UPPER TROUGH IS 
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS NEAR THE 
NORTHERN PART OF THE WAVE AXIS MAINLY OVER LAND. 

TROPICAL WAVE FROM 09N TO 17N ALONG 115W MOVING W 10-12 KT. 
SATELLITE IMAGES SHOW AN ASSOCIATED AREA OF LOW TO MID LEVEL 
CYCLONIC TURNING WITH SOME EVIDENCE OF A MID-LEVEL LOW NEAR 
13N115W. SCATTERED MODERATE TO STRONG CONVECTION IS OCCURRING AT 
THE NORTHERN END OF THE WAVE WITHIN 75 NM OF 15N115W. CONVECTION 
WAS BEING SHEARED BY STRONG SLY WINDS ALOFT ON THE E SIDE OF AN 
UPPER LOW...WHICH IS UNFAVORABLE FOR TROPICAL CYCLOGENESIS.  

TROPICAL WAVE FROM 07N TO 16N ALONG 133W IS MOVING W 15 KT. 
CONVECTION HAS INCREASED IN COVERAGE AND ORGANIZATION OVER THE 
PAST SEVERAL HOURS WITH WELL DEFINED MID LEVEL TURNING NOTED
NEAR 12N134W. UPPER DIFFLUENCE IS ENHANCING THIS CONVECTIVE 
ACTIVITY. A HIGH RESOLUTION QUIKSCAT PASS FROM 1418 UTC 
INDICATED LOW PRES MAY BE DEVELOPING ALONG THE WAVE. 

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...08N78W TO 
07N95W TO 09N108W TO 14N125W TO 09N140W. SCATTERED MODERATE TO 
STRONG WITHIN 240 NM W OF TROPICAL WAVE ALONG 133W FROM 08N TO 
14N. SCATTERED MODERATE TO STRONG N OF 04N E OF 80W. SCATTERED 
MODERATE ISOLATED STRONG FROM 05N TO 13N BETWEEN 80W AND 
90W...AND WITHIN 120 NM S OF THE AXIS BETWEEN 103W AND 
110W...AND FROM 08N TO 11N BETWEEN 120W AND 130W. 

...DISCUSSION...

A HIGHLY DIFFLUENT UPPER PATTERN OVER THE DEEP TROPICS IS 
ENHANCING CONVECTION NEAR THE TROPICAL WAVE ALONG 133W AND OVER 
THE ITCZ WEST OF 125W. AS NOTED ABOVE A HIGH RESOLUTION QSCAT 
PASS AT 1418 UTC INDICATED A SURFACE LOW MAY BE DEVELOPING. 
IN ADDITION THIS PASS INDICATED NE-E WINDS OF 20-25 KT IN THE 
VICINITY OF THE WAVE IN RESPONSE TO THE STEEPENED PRESSURE 
GRADIENT BETWEEN IT AND THE SUBTROPICAL RIDGE. THE HIGHER 
WINDS ARE REFLECTED IN THE HIGH SEAS FORECAST. THIS WAVE IS 
EXPECTED TO CONTINUE W AT 10-15 KT WITH THE 20-25 KT FLOW 
GRADUALLY SHIFTING W WITH IT. 

DIFFLUENT UPPER FLOW OVER NORTHERN MEXICO HAS PRODUCED 
WIDESPREAD MULTI LEVEL BROKEN TO OVERCAST CLOUDINESS OVER THIS 
AREA. OVERNIGHT CONVECTION HAS DIMINISHED BUT IS EXPECTED TO 
DEVELOP AGAIN LATER TODAY. 

BESIDES THE TROPICAL WAVES AND ITCZ RELATED CONVECTION...MUCH OF 
THE REMAINDER OF THE BASIN IS EXPERIENCING FAIR WEATHER. 

STRONG TRADES ACROSS THE CARIBBEAN CONTINUE TO FAVOR ENHANCED 
FLOW THROUGH THE GULF OF PAPAGAYO. A 1518 UTC ASCAT PASS 
REVEALED WINDS OF 15-20 KT IN THE GAP. HOWEVER...THIS PASS 
OCCURRED NEAR THE EXPECTED DIURNAL MINIMUM OF THIS GAP FLOW...SO 
WINDS MAY BE SLIGHTLY STRONGER AT THE MOMENT. HOWEVER...NWP 
MODELS AGREE IN DIMINISHING WINDS BELOW 20 KT WITHIN THE NEXT 36 
HOURS.

$$
COBB